Chitinase-3-like protein 1 (CHI3L1) is a secreted glycoprotein produced by immune cells and tumor cells that plays important roles in inflammatory responses, tissue remodeling, and tumor progression. Elevated circulating levels of CHI3L1 have been reported in various inflammatory diseases and cancers, suggesting its potential as a diagnostic and therapeutic target. In this study, an antibody that specifically recognizes CHI3L1 was investigated for its physicochemical stability and in vivo characteristics. The stability of the antibody was evaluated under stress conditions, and formulation screening was performed to assess factors influencing physicochemical stability. To further examine its in vivo behavior, biodistribution studies were performed in a mouse tumor model, and systemic distribution was monitored over time. These studies provide initial insights into the developability and in vivo characteristics of a CHI3L1-targeting antibody, supporting the further development of CHI3L1-targeted therapeutic strategies.